1. Field of the Invention
The present invention generally relates to pumps and, more particularly, is concerned with a suction dredge pump apparatus having a plurality of expandable and contractible drums connected to separate compartments of a manifold through which the fluid mixture being pumped flows.
2. Description of the Prior Art
The use of heavy equipment, such as bulldozers, backhoes and loaders is common in large scale mining operations. However, investment in such heavy equipment is not economically feasible in small scale placer mining. Instead, a less expensive means, such as a pump, may be utilized to lift a fluid mixture, such as water, sand, gravel and dirt, from a riverbed or other location to a discharge area where gold or another desired material may be separated from the other components of the fluid mixture.
A screw-type pump or an impeller-type pump could be employed to lift the fluid mixture from the riverbed to the discharge area, but the sand, gravel and dirt of the fluid mixture is likely to have an undesirable adverse effect on the screw or impeller. Therefore, it is desirable that there be no contact between the fluid mixture and the means used to lift the fluid mixture from the riverbed to the discharge area.
Bellows-type pumps utilizing a plurality of bellows that are expanded and contracted in a cycle to achieve a relatively uniform flow of fluid are known in the prior art. One example of this type of pump is disclosed in U.S. Pat. No. 2,363,410 to Gill, Sr. The bellows-type pump of Gill, Sr. has four bellows that reach maximum compression and expansion at different successive quarter revolutions of a shaft to achieve a relatively continuous flow of fluid from the pump. However, in this pump, the fluid that is being pumped has to enter the bellows. This requirement would likely make the Gill, Sr. pump unsuitable for application in a placer mining operation where the sand, gravel and dirt of the fluid mixture, by entering the bellows, would be likely to cause serious damage to the pump.
Consequently, the need exists for a pump which will avoid the drawbacks of the prior art and be suitable for small scale mining operations.